1. Field of the Invention
This invention relates to a process for working up aqueous electrolyte-containing suspensions of highly swellable layer silicates.
2. Description of the Related Art
Processes for working up highly swellable layer silicates, such as hectorites, are known. In these processes, the layer silicates are supposed to be isolated and separated off from the starting suspension in electrolyte-free form.
In known processes, the mother liquor is first separated off by filtration in filter presses, particularly membrane filter presses. The layer silicates remain in the filter cake as a gel-like mass together with part of the adhering mother liquor of high electrolyte content. In order to isolate the layer silicates from the filter cake in electrolyte-free form, it is standard practice to wash out the filter cake with water. However, under the effect of the electrolytes still present, the layer silicates begin to swell considerably, clogging the pores of the filter medium so that filtration becomes very difficult or even impossible. Because of these difficulties, the layer silicates can only be worked by a very laborious and complicated filtration and washing process.